root
/
spring-framework
mirror of https://github.com/spring-projects/spring-framework.git
1
0
Fork 0
Code Issues Actions Packages Projects Releases Wiki Activity

Document heartbeat support in SockJS

This commit is contained in:
Rossen Stoyanchev 2014-03-23 23:13:13 -04:00
parent b1a0b38d8f
commit f25b7df552
1 changed files with 37 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
src/asciidoc/index.adoc
View File

@ -37355,25 +37355,26 @@ be cached. For details on how to enable it see the
https://github.com/sockjs/sockjs-client[SockJS client] page.
====
[[websocket-fallback-cors]]
==== SockJS and CORS
[[websocket-fallback-sockjs-heartbeat]]
==== Heartbeat Support in SockJS
The SockJS protocol uses CORS for cross-domain support in the XHR streaming and
XHR polling transports. CORS headers are automatically added to SockJS requests
for transports that require it as well as for the initial `"/info"` request.
The SockJS protocol requires servers to send heartbeat messages to preclude proxies
from concluding a connection is hung. The Spring SockJS configuiration has a property
called `heartbeatTime` that can be used to customize the frequency. By default a
heartbeat is sent after 25 seconds assuming no other messages were sent on that
connection. This 25 seconds value is in line with the following
http://tools.ietf.org/html/rfc6202[IETF recommendation] for public Internet applications.
Spring's `SockJsServce` implementation checks for the presence of the CORS
`"Access-Control-Allow-Origin"` header in the response. If present, no new CORS
headers are added, essentially assuming that CORS support is configured
centrally, e.g. through a Servlet Filter. Otherwise the following are added:
[NOTE]
====
When using STOMP over WebSocket/SockJS, if the STOMP client and server negotiate
heartbeats to be exchanged, the SockJS heartbeats are disabled.
====
* `"Access-Control-Allow-Origin"` - intitialized from the value of the "origin" request header or "*".
* `"Access-Control-Allow-Credentials"` - always set to `true`.
* `"Access-Control-Request-Headers"` - initialized from values from the equivalent request header.
* `"Access-Control-Allow-Methods"` - the HTTP methods a transport supports (see `TransportType` enum).
* `"Access-Control-Max-Age"` - set to 31536000 (1 year).
For the exact implementation, see `addCorsHeaders` in `AbstractSockJsService`.
The Spring SockJS support also allows configuring the `TaskScheduler` to use
for scheduling heartbeats tasks. The task scheduler is backed by a thread pool
with default settings based on the number of available processors. Applications
should consider customizing the settings according to their specific needs.
[[websocket-fallback-sockjs-servlet3-async]]
==== SockJS and Servlet 3 Async Support
@ -37403,6 +37404,26 @@ defined in `AbstractSockJsSession`. If you need to see the stack traces, set tha
log category to TRACE.
====
[[websocket-fallback-cors]]
==== SockJS and CORS
The SockJS protocol uses CORS for cross-domain support in the XHR streaming and
XHR polling transports. CORS headers are automatically added to SockJS requests
for transports that require it as well as for the initial `"/info"` request.
Spring's `SockJsServce` implementation checks for the presence of the CORS
`"Access-Control-Allow-Origin"` header in the response. If present, no new CORS
headers are added, essentially assuming that CORS support is configured
centrally, e.g. through a Servlet Filter. Otherwise the following are added:
* `"Access-Control-Allow-Origin"` - intitialized from the value of the "origin" request header or "*".
* `"Access-Control-Allow-Credentials"` - always set to `true`.
* `"Access-Control-Request-Headers"` - initialized from values from the equivalent request header.
* `"Access-Control-Allow-Methods"` - the HTTP methods a transport supports (see `TransportType` enum).
* `"Access-Control-Max-Age"` - set to 31536000 (1 year).
For the exact implementation, see `addCorsHeaders` in `AbstractSockJsService`.
[[websocket-fallback-sockjs-explained]]
==== How SockJS Works
This is a question beyond the scope of this document. The SockJS protocol